Hierarchial Datagrids in WPF

I have a hierarchical Data grid.

<DataGrid Name="dgList" ItemsSource="{Binding List1}" Grid.Row="0" Margin="0,0,0,0"
                      CanUserAddRows="False" AutoGenerateColumns="False" IsReadOnly="True" ><DataGrid.Columns><DataGridTextColumn Header="Sub System" Binding="{Binding Path=Name}" IsReadOnly="True"></DataGridTextColumn></DataGrid.Columns><DataGrid.RowDetailsTemplate><DataTemplate><DataGrid Name="dgList2" AutoGenerateColumns="False" ItemsSource="{Binding Name1}" CanUserAddRows="False" IsReadOnly="True" ><DataGrid.Columns><DataGridTextColumn MinWidth="250" Header="Name3" Binding="{Binding Path=Name3}"></DataGridTextColumn></DataGrid.Columns><DataGrid.RowDetailsTemplate><DataTemplate><DataGrid Name="List2" AutoGenerateColumns="False" ItemsSource="{Binding List3}" CanUserAddRows="False" IsReadOnly="True" ><DataGrid.Columns><DataGridTextColumn MinWidth="250" Header="FN" Binding="{Binding Path=FirstName}"></DataGridTextColumn><DataGridTextColumn MinWidth="250" Header="LN" Binding="{Binding Path=LastName}"></DataGridTextColumn></DataGrid.Columns></DataGrid></DataTemplate></DataGrid.RowDetailsTemplate></DataGrid></DataTemplate></DataGrid.RowDetailsTemplate></DataGrid> 

The grid works fine,Clicking on the row would expand the sublist.

But is it possible to have an arrow or + plus on the left column which would indicate that there are more rows.